How do you know if someone blocked your number android

Not really. It all depends on how it was blocked. Some systems block calls by routing to voicemail (rare) but that doesn't sound like it's happening here. If it was on a cell phone number, you're likely out of luck because in those systems it just stops that number coming in. In this case, the best thing to do is to call with another number (cell, lan line, etc). If it's critical - you can even purchase a cheap disposable pre-paid phone (i.e. a burner) to try to contact. Good luck!